SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6fcb176c5c6d1ecfdf214220836528a25d623083b8a5296ed0b2ff1963a213c' 
  AND token = 'PHHj+vHQzDxx1V7owohZWJucIiSjQR0kgurqXw5NPc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}